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Re: remote protocol extension for step out of range
- To: jtc at redback dot com
- Subject: Re: remote protocol extension for step out of range
- From: Andrew Cagney <ac131313 at cygnus dot com>
- Date: Thu, 01 Feb 2001 11:57:39 -0800
- Cc: gdb at sourceware dot cygnus dot com
- References: <email@example.com> <firstname.lastname@example.org>
"J.T. Conklin" wrote:
> >>>>> "jtc" == J T Conklin <email@example.com> writes:
> jtc> Step-out-of-range only commands might look like:
> jtc> ENN,SS..SS,EE..EE[,AA...AA]
> jtc> or:
> jtc> eSS...SS,EE..EE[,AA..AA]
> jtc> Which would step from the PC and repeat until it moved out of the
> jtc> range described by SS..SS and EE..EE. I've also preserved the ability
> jtc> to set the initial PC like the existing step commands for parallelism;
> jtc> I don't expect that GDB will use it either.
> jtc> To be able to successfully probe for this command, there should be a
> jtc> return value. An OK or EXX response should do. Older stubs would
> jtc> return "" as they do for all unrecognized commands.
> It turned out to be trival to implement the above. I've enclosed a
> patch for review. The guts are ~50 lines, including comments. The
> rest is required for the CLI so the user can enable and disable the
> new packets.
> I welcome any comments,
I'm wondering about is how this works in a threaded environment. This
continuation is very thread unfriendly (so is the underlying code so I'm
fighting an up hill battle here :-). That was the reason for thinking
of an explicit breakpoint packet - so it could eventually be bound to a
specific thread. Given that this packet is mostly reflecting the way
the GDB works, I suspect doing this different is beyond the scope of
your proposed change.
How will this packet work with something like the sparc where, to do a
correct continue you need to set both PC and NPC. Consequently a sparc
does a resume by setting PC/NPC with register-write packets and then
does the continue.
With regard to the syntax, can it be specified in a way that is
extensable? The ``T'' reply packet can bundle up all sorts of
information. If we're going to have a new continue packet can the
syntax be such that it allows similar extensions?
Dig dig dig. I've a local stub that uses the T packet to send back
_all_ the registers (none of this ``Gg'' stuff :-). It was also tweeked
to allow the syntax <RENUM>!<NETWORK-ORDERD-VALUE> instead of
``<REGNUM>=<TARGET-ORDERD-VALUE>'' Should the [eE] packet syntax mirror
that of the ``T'' reply? Perhaphs not the register values but at least
the ability to be extensable?